PLC (Programmable Logic Controller)

PLC has the advantages of stability and reliability, low price, complete functions, flexible and convenient application, and convenient operation and maintenance. The fundamental reason why it can occupy the market for a long time. We will focus on several issues below and study its development trend.
The hardware of the PLC controller itself adopts a building block structure, and the product structure of each manufacturer is similar. Taking Japan’s Omron C200HE as an example, it is a bus frame architecture. The CPU motherboard is equipped with a CPU module, and other slots are equipped with I/O modules; if the I/O module.
In addition to the general DI/DO, and AD/DA modules, the I/O modules in the PLC have also developed a series of I/O modules with special functions, which opens the way for PLCs to be used in all walks of life, such as for barcodes ASCII/BASIC template for identification, PID template for feedback control, high-speed counting template for operation control, machining, single-axis position control template, dual-axis position control template, cam positioner, RFID interface, etc.,
The CPU in the PLC cooperates with the memory to complete the control function. It differs from the DCS system, which deals with parameters such as temperature, pressure, flow, etc. It adopts a fast circuit scanning period, generally 0.1~0.2s, and a faster scanning period of 50ms or less. It is a digital sampling control system.

Industrial control instrument
Focus on developing main control system devices based on Fieldbus technology and intelligent instruments, special and special automation instruments; comprehensively expand service fields, and promote the digitization, intelligence, and networking of instrumentation systems.

Electrical instrument
Electrical instruments and meters focus on developing long-life electric energy meters, electronic watt-hour meters, special-purpose electric measuring instruments, and automatic management systems for power grid metering.

Test instrument
Scientific testing instruments focus on developing process analysis instruments, environmental monitoring instruments, industrial furnace energy-saving analysis instruments, auto parts dynamic balance, power test and vehicle performance detectors, geodetic instruments, and electronic speed testers required by basic industries. , measuring GPS and other new products such as testing machines and laboratory instruments.

Environmental protection instruments
Environmental protection instrumentation focuses on developing environmental protection monitoring instrumentation, sampling system, and environmental monitoring automation control system for the atmospheric and water environment.

Electrical measuring instrument
Information technology electrical measuring instrument mainly develops software-based and intelligent technology of electrical measuring instrument, bus-type automated test technology, comprehensive automatic test system, new component measurement technology and test instrument, online test technology, information test technology, multimedia measurement technology, And the related test equipment, power monitoring, and management technology.

Converter
The converter is a power control device that uses frequency conversion technology and microelectronics technology to control the AC motor by changing the motor’s working power supply frequency. 
The converter is composed mainly of rectification (AC to DC), filtering, inverter (DC to AC), braking, drive, detection, and micro-processing. The inverter adjusts the voltage and frequency of the output power supply by switching on and off the internal IGBT and provides the required power supply voltage according to the motor’s actual needs, thereby achieving energy saving and speed regulation. In addition, the converter also has many protection functions, such as overcurrent, overvoltage, overload protection, etc. With the continuous improvement of industrial automation, frequency converters have also been widely used.

Servo Motor
The Servo motor is the engine that controls the operation of mechanical components in the servo system and is an auxiliary motor indirect speed change device.
The servo motor can control the speed, the position accuracy is very accurate, and it can convert the voltage signal into torque and speed to drive the control object. The rotor speed of the servo motor is controlled by the input signal and can respond quickly. In the automatic control system, it is used as an executive element. It has the characteristics of a short electromechanical time constant and high linearity, which can convert the received electrical signal into the motor shaft. It is divided into two categories: DC and AC servo motors. Its main feature is that when the signal voltage is zero, there is no rotation phenomenon, and the speed decreases uniformly with the increase of torque.